I have had this brake controller for 5 years. So while I was getting evrything ready for our first camping trip of the year I noticed a whine coming from the brakes of the trailer, while parked and plugged into the truck. I headed out and noticed the display showed n.c. I think this stands for no connection, idk, so the trailer brakes do not work in conjunction with the truck brakes but I can manually actuate them with the little toggle lever. Any ideas?

Thanks.

 

I think the first thing to look for is a broken wire some were on the trailer. Use a meter to find the short or broken wire. It could also be a bad ground on the trailer.
That is the first area I would look at.

 

Last time I had a problem I went to a friend with a trailer and connected up his harness to my truck. Controller worked fine with his rig. It was an easy way to figure out that the problem was with my trailer.

 

I just took my 5th wheel out and the display on the controler turned red and said "no connection" (or something like that). When I stopped, I had no trailer breaks. I then unplugged the 7-pin connector and cleaned it out, but no change. Then I noticed a small section of bare/damaged wire on the trailer. I fixed that, and the system works great again....In other words, I would also look for a broken or damaged wire(s).

 

I had the same problem with my Prodigy a year or two ago. They worked when I pushed the lever, but wouldn't work in conjunction with the truck brakes. I found a loose connection inside the trailer plug. I fixed that, and all was good.

 

I had a controller do that. Manually worked fine but not with the brake pedal. Turns out the guy who wired it did not wire the red wire from the controller to the proper brake wire. The controller needed to have a connection to a wire that activated when the brake pedal was depressed (the circuit that triggered the brake lights). He wired it to a wrong wire. Once I fixed the wiring, it worked fine. I would check that wire to see if it came loose because without it the brake won't activate.

 

Mine did that and the magnets on the brakes were worn out.